共查询到20条相似文献，搜索用时 15 毫秒
1.
The hydrodynamic equations of positive and negative dust, Boltzmann electron and ion density distribution, and Poisson equation are used along with the reductive perturbation method to derive a cylindrical Kadomtsev-Petviashvili (CKP) equation. G′/G expansion method is used to obtain a new class of solutions. At certain condition, the solutions degenerate to solitary wave solutions. The effects of the physical parameters on the characteristics of solitary pulses are examined. The results give elucidation of the properties of dust acoustic solitary pulses in multicomponent space plasmas, particularly in interstellar dust clouds in a galactic disk and astrophysical plasma systems. 相似文献
2.
The formation and propagation of dust-acoustic (DA) solitary and rogue waves are studied in a non-relativistic degenerate Thomas-Fermi thermal dusty plasma incorporating transverse velocity perturbation effects. The electrons and ions are described by the Thomas-Fermi density distributions, whereas the dust grains are taken as dynamic and classical. By using the reductive perturbation technique, the cylindrical Kadomtsev-Petviashvili (CKP) equation is derived, which is then transformed into a Korteweg-deVries (KdV) equation by using appropriate variable transformations. The latter admits a solitary wave solution. However, when the carrier waves frequency is much smaller than the dust plasma frequency, the DA waves evolve into the nonlinear modulation instability, generating modulated wave packets in the form of Rogue waves. For the study of DA-rogue waves, the KdV equation is transformed into a self-focusing nonlinear Schrödinger equation. The variation of dust temperature and the electron density affects the nonlinearity and dispersion coefficients which suppress the amplitudes of the DA solitary and rogue waves. The present results aim to describe the nonlinear electrostatic excitations in astrophysical degenerate dense plasma. 相似文献
3.
Propagation of two dimensional cylindrical fast magnetoacoustic solitary waves in a warm dust plasma
A set of multi-fluid equations and Maxwell’s equations are carried out to investigate the properties of nonlinear fast magnetoacoustic solitary waves with the combined effects of dusty plasma pressure and transverse perturbation in the bounded cylindrical geometry. The reductive perturbation method has been applied to the dynamical system causeway and the derived two dimensional cylindrical Kadomtsev–Petviashvili equation (CKP) predicts different natures of solitons in complex plasma. Under a suitable coordinate transformation the CKP equation can be solved analytically. The change in the soliton structure due to mass of dust, ion temperature, ion density, and dust temperature is studied by numerical calculation of the CKP equation. It is noted that the dust cylindrical fast magnetoacoustic solitary waves in warm plasmas may disappear slowly because of an increase in dust mass. The present analysis could be helpful for understanding the nonlinear ion-acoustic solitary waves propagating in interstellar medium and pulsar wind,which contain an excess of superthermal particles. 相似文献
4.
Using the standard reductive perturbation technique, nonlinear cylindrical and spherical Kadomtsev-Petviashvili (KP) equations are derived for the propagation of ion acoustic solitary waves in an unmagnetized collisionless plasma with nonthermal electrons and warm ions. The influence of nonthermally distributed electrons and the effects caused by the transverse perturbation on cylindrical and spherical ion acoustic waves (IAWs) are investigated. It is observed that the presence of nonthermally distributed electrons has a significant role in the nature of ion acoustic waves. In particular, when the nonthermal distribution parameter ?? takes certain values the usual cylindrical KP equation (CKPE) and spherical KP equation (SKPE) become invalid. One then has to have recourse to the modified CKPE or SKPE. Analytical solutions of both CKPE and SKPE and their modified versions are discussed in the present paper. The present investigation may have relevance in the study of propagation of IAWs in space and laboratory plasmas. 相似文献
5.
The nonlinear propagation of ion-acoustic solitary and shock waves in a dissipative, nonplanar quantum plasma comprised of electrons, positrons, and ions are studied. A modified Korteweg-de Vries Burgers equation is derived in the limit of low frequency and long wavelength by taking into account the kinematic viscosity among the plasma constituents. It is shown that this plasma system supports the propagation of both compressive and rarefactive nonlinear waves. The effects of variation of various plasma parameters on the time evolution of nonplanar solitary waves, the profile of shock waves, and the nonlinear structure induced by the collision of solitary waves are discussed. It is found that these parameters have significant effects on the properties of nonlinear waves in cylindrical and spherical geometries, and these effects for compressive and rarefactive nonlinear waves are obviously different. 相似文献
6.
A theoretical investigation has been made on obliquely propagating dust-ion-acoustic solitary waves (DIASWs) in magnetized
dusty electronegative plasma containing Boltzmann electrons, trapped negative ions, cold mobile positive ions, and arbitrarily
charged stationary dust. The reductive perturbation method has been employed to derive the modified Zakharov-Kuznetsov (MZK)
equation which admits solitary wave solution under certain conditions. The multi-dimensional instability of these solitary
waves is also studied by the small-k (long wavelength plane wave) perturbation-expansion technique. The basic properties (speed, amplitude, width, instability,
etc.) of small but finite amplitude DIASWs are significantly modified by the effects of external magnetic field, obliqueness,
polarity of dust, and trapped negative ions. The implications of our results in space and laboratory plasmas are briefly discussed. 相似文献
7.
H. Alinejad 《Astrophysics and Space Science》2012,337(1):223-229
A theoretical investigation is developed to study the existence, formation and basic properties of arbitrary amplitude dust
ion-acoustic solitary potentials in a dusty plasma consisting of warm ions, trapped electrons and immobile negative (positive)
dust particles. It is found a definite interval for the Mach number for which solitary waves exist and depend sensitively
on the ion temperature and negative (positive) dust concentration. In addition, the effects of ion temperature, two oppositely
charged dust species and resonant electrons on the shape of the solitary waves are also investigated extensively. For both
cases of negative and positive dust grains, the effect of ion temperature is found to be destructive for the formation of
localized structures. Further, the amplitude of the solitary structures decreases (increases) with the increase in the negative
(positive) dust concentration. 相似文献
8.
Investigation of nonlinear wave modulation of electron-acoustic solitary wave packets in planar as well as nonplanar geometry is carried out for an unmagnetized two temperature plasma composed of cold and hot (featuring q-nonextensive distribution) electrons with stationary ions. It is shown that in such plasma, propagation of EA wave packets is governed by a modified NLSE which accounts for the geometrical effect and the nonextensivity of the hot electron species. It is found that the nature of the modulational instabilities would be significantly modified due to the geometrical effects, density ratio α of the hot-to-cold electrons species as well as their temperature ratio θ. Also, there exists a modulation instability period for the cylindrical and spherical envelope excitations, which does not exist in the one-dimensional case. Furthermore, spherical EA solitary wave packets are more structurally stable to perturbations than the cylindrical ones. The relevance of the current study to EA wave modulation in auroral zone plasma is highlighted. 相似文献
9.
H. Alinejad 《Astrophysics and Space Science》2012,339(2):249-254
The effects of dust polarity and superthermal electrons are incorporated in the study of dust ion-acoustic (DIA) solitary
waves (SWs) as well double layers (DLs) in a dusty plasma containing warm adiabatic ions, superthermal electrons, and arbitrarily
(positively or negatively) charged immobile dust. Based on the energy-like integral equation, a new relationship between the
localized electrostatic disturbances and dust polarity is derived. It is shown that there exists rarefactive SWs and DLs with
qualitatively different structures in a way that depends on the population of superthermal electrons. As the electrons evolve
their thermodynamic equilibrium, the localized structures are found with larger amplitude. It is also found that their amplitude
increases (decreases) with the increase in the negative (positive) dust number density. 相似文献
10.
Nonlinear properties of ion-acoustic (IA) shock are studied by incorporating the effects of electron nonextensivity in a warm electronegative plasma, whose constituents are the inertial positive/negative ions and q-distributed electrons. For this purpose, the evolution equations are solved to obtain Kadomtsev-Petviashvili (KP) Burgers equation by using the reductive perturbation technique and its solution by the tanh method. Furthermore, the conditions for the existence of oscillatory and monotonic shocks are discussed. Numerically, it is found that IA shock propagation characteristics are significantly modified by the variation of plasma parameters, such as, the effects of electron nonextensivity, the positive and negative ion-to-electron temperature ratios (θ i ,θ n ), respectively. The former also affect the dispersion, dissipation and nonlinearity coefficients of the KPB equation involving the IA shocks. The present analyses could be useful for understanding the nonlinear shock wave excitations in space and laboratory plasmas, where two distinct groups of ions are present. 相似文献
11.
Detection of ionospheric perturbation due to a soft gamma ray repeater SGR J1550-5418 by very low frequency radio waves 总被引：1，自引：0，他引：1
Sushanta K. Mondal Sandip K. Chakrabarti Sudipta Sasmal 《Astrophysics and Space Science》2012,338(2):259-264
The properties of cylindrical and spherical dust acoustic (DA) solitary and shock waves in an unmagnetized electron depleted
dusty plasma consisting of inertial dust fluid and ions featuring Tsallis statistics are investigated by employing the reductive
perturbation technique. A Korteweg-de Vries Burgers (KdVB) equation is derived and its numerical solution is obtained. The
effects of ion nonextensivity and dust kinematic viscosity on the basic features of DA solitary and shock waves are discussed
in nonplanar geometry. It is found that nonextensive nonplanar DA waves behave quite differently from their one-dimensional
planar counterpart. 相似文献
12.
We have studied the nonlinear propagation of dust ion-acoustic (DIA) waves in a dusty multi-ion dense plasma (with the constituents being degenerate, either non-relativistic or ultra-relativistic) and the propagation of such waves have been investigated by the reductive perturbation method. From the stationary solution of the Korteweg de-Vries (K-dV) equation and Burgers’ equation the nonlinear waves (specially, solitary and shock waves) have been found to be formed in the dusty plasma system under consideration. It has shown that the basic features of these waves are significantly modified by both the positive and negative ions and dust number densities, the degenerate of the constituents. The implications of our results have been briefly discussed. 相似文献
13.
Small amplitude dust-acoustic solitary waves in an unmagnetized dusty plasma consisting of electrons and two temperature ions obeying the q-nonextensive distribution are investigated. Employing reductive perturbation method, the Korteweg-de Vries (KdV) equation is derived. From the solitonic solutions of KdV equation, the influence of nonextensivity of electrons as well as ions and dust concentration on the amplitude and width of dust-acoustic solitary waves has been studied. It is observed that both positive and negative potential dust acoustic solitary waves occur in this case. The modified KdV (mKdV) equation is derived in order to examine the solitonic solutions for the critical plasma parameters for which KdV theory fails. The parametric regimes for the existence of mKdV solitons and double layers (DLs) have also been determined. Positive potential double layers are found to occur in the present study. 相似文献
14.
H. Alinejad 《Astrophysics and Space Science》2011,331(2):611-618
The effects of dust charge fluctuations and deviations from isothermality of electrons are incorporated in the study of nonlinear
dust ion-acoustic waves. Deviations from isothermality of electrons are included in this model as a result of nonlinear resonant
interaction of the electrostatic wave potential with electrons during its evolution. The basic properties of stationary structures
are studied by employing the reductive perturbation method, and conditions for the formation of small but finite amplitude
dust ion-acoustic solitary waves in the space dusty plasma situations are clearly explained. It is shown that a more depletion
of the background free electrons owing to the attachment of these electrons to the surface of the dust grains during the charging
process can lead to the formation of solitary waves with smaller amplitude. Furthermore, effects of the dust charge fluctuation
and deviations from isothermality of electrons show a non-uniform behavior for the amplitude of solitary waves in transition
from the Boltzmann electron distribution to a trapped electron one. It is also found that the dust charge fluctuation caused
by trapped as well as free electrons is a source of dissipation, and is responsible for the formation of the dust ion-acoustic
shock waves. 相似文献
15.
Nonlinear propagation of cylindrical and spherical dust-acoustic solitons in an unmagnetized dusty plasma consisting of cold
dust grains, superthermal ions and electrons are investigated. For this purpose, the standard reductive perturbation method
is employed to derive the cylindrical/spherical Korteweg-de-Vries equation which governs the dynamics of dust-acoustic solitons.
The effects of nonplanar geometry and superthermal distributions on the cylindrical and spherical dust acoustic solitons structures
are also studied by numerical calculation of the cylindrical/spherical Korteweg-de-Vries equation. 相似文献
16.
The longitudinal fast solitary waves induced by weakly relativistic positron showers of astrophysical origin are studied in a plasma system contaminated with some massive impurities in presence of superthermal effects. The superthermal effects are due to the high energy electrons. The impurities are dust corpuscles with positive and negative charges. It is noticed that increase in the kappa parameter of electrons and relativistic streaming factor of weakly relativistic positron shower, negative dust concentration invoke an enhancement in the strength of solitary wave. On the other hand increase in the shower’s temperature as well as positive dust concentration diminish the solitary hump strength. It is worth to mention that only hump type compressive fast solitary waves are predicted by our model, for the given set of plasma parameters, because the convective coefficient of the nonlinear governing equation for solitary wave remains positive in considered regime of interaction for plasma and positron shower. Our calculations in linear regime predict both the fast and slow positron shower induced longitudinal, electrostatic perturbations. Our results may be of importance in understanding the nonlinear propagation of waves in doped astrophysical superthermal plasmas with relativistic positron showers. 相似文献
17.
The behavior of quantum dust ion-acoustic (QDIA) shocks in a plasma including inertialess quantum electrons and positrons, classical cold ions and stationary negative dust grains are studied, using a quantum hydrodynamic model (QHD). The effect of dissipation due to the viscosity of ions is taken into account. The propagation of small but finite amplitude QDIA shocks is governed by the Kortoweg-de Vries-Burgers (KdVB) equation. The existence regions of oscillatory and monotonic shocks will depend on the quantum diffraction parameter (H) and dust density (d) as well as dissipation parameter (η 0). The effect of plasma parameters (d,H,η 0), on these structures is investigated. Results indicate that the thickness and height of monotonic shocks; oscillation amplitude of the oscillatory shock wave and it’s wavelength effectively are affected by these parameters. Additionally, the possibility of propagation of both compressive and rarefactive shocks is investigated. It is found that depending on some critical value of dust density (d c ), which is a function of H, compressive and rarefactive shock waves can’t propagate in model plasma. The present theory is applicable to analyze the formation of nonlinear structures at quantum scales in dense astrophysical objects. 相似文献
18.
Hamid Reza Pakzad Kurosh Javidan Mouloud Tribeche 《Astrophysics and Space Science》2014,352(1):185-191
The propagation of cylindrical and spherical electron acoustic (EA) shock waves in unmagnetized plasmas consisting of cold fluid electrons, hot electrons obeying a superthermal distribution and stationary ions, has been investigated. The standard reductive perturbation method (RPM) has been employed to derive the cylindrical/spherical Korteweg-de-Vries-Burger (KdVB) equation which governs the dynamics of the EA shock structures. The effects of nonplanar geometry, plasma kinematic viscosity and electron suprathermality on the temporal evolution of the cylindrical and spherical EA shock waves are numerically examined. 相似文献
19.
M. Shalaby S. K. El-Labany E. F. El-Shamy M. A. Khaled 《Astrophysics and Space Science》2010,326(2):273-279
The propagation of solitary waves in an unmagnetized collisional dusty plasma consisting of a negatively charged dust fluid,
positively charged ions, isothermal electrons, and background neutral particles is studied. The ionization, ion loss, ion–neutral,
ion–dust, and dust–neutral collisions are considered. Applying a reductive perturbation theory, a damped Korteweg–de Vries
(DKdV) equation is derived. On the other hand, at a critical phase velocity, the dynamics of solitary waves is governed by
a damped modified Korteweg–de Vries (DMKdV) equation. The nonlinear properties of solitary waves in the two cases are discussed. 相似文献
20.
Linear and nonlinear propagation of dust drift waves are investigated in the presence of Cairns and Kappa distributed ion population and Boltzmannian electrons. It is found the frequency of the dust drift wave is greatest for the Cairns, intermediate for Kappa and the least for the Maxwellian distributed ions. Using the drift approximation, a nonlinear equation is derived for the dust drift shock waves which reduces to a Korteweg-de Vries-Burgers (KdVB)-like equation in the comoving frame of reference. The solution of the KdVB-like equation is obtained using the tanh method. It is found that the non-Maxwellian ion population, dust neutral collision frequency as well as the inverse dust density scale length inhomogeneity alter the propagation characteristics of the nonlinear dust drift shock waves. Interestingly, it is found that the non-Maxwellian ion population modifies the scale lengths over which the nonlinear structures are formed. The work presented here may be useful to understand the low frequency electrostatic shock waves in inhomogeneous dusty plasmas such as those found in planetary environments. 相似文献